1. Field of the Invention
This invention relates generally to devices and constructs used to, effect subterranean drainage from building structures and entrenchments, such as walls, footings and foundations, where seepage and ground water are a problem, and also under garage and basement floors where overburden of concrete exacerbates the drainage problem by frustrating most existing devices or their filtering adjuncts. More specifically, this invention embodies a filtered drain improvement using a simplified fabric separation device that requires a far less extensive manufacturing process than the present-day art; and yet, it can sustain great overburden and is inherently pliable enough to be rolled and used as a flexible drain assembly (“blanket-drain”) over and around structures that would otherwise have to be served by more cumbersome and costly systems.
2. Discussion of Relevant Art
It has long been a practice, in the construction industry, to provide some form of drainage to subterranean structures. Ground water seepage remains a problem in most non-arid regions of the world; and, building footings, garage floors (multi-level) and walls, facing surface and subsurface waters, have been most susceptible to water incursions. Many drainage devices have been provided, as well as adjuncts thereto, in order to provide adequate carry-off (“transport”) of these undesired waters; some of the adjuncts provide a modicum of filtration of the minute particulate that is so common in most soils. In many cases, the filtering mechanisms must employ more than one medium of sifting-filtering material because of the varied aggregate and soil or sand mix in which the construction takes place. Until recently, the uses of prefabricated drain devices, combined with overlays of unique geo-textiles, that filter out fine particulate, did not obviate the need for vast amounts of stone to be interposed the structure and earth. Many attempts have thus been made to create drainage mechanisms that will take advantage of new materials for filtration, but nonetheless have fallen short of providing a system or assembly that has a broad spectrum of usage (“multi-usage”), such as for placement on vertical surfaces, under concrete floors (above and below ground) and for wrapping around structures such as conduits.
Five disclosures are germane to this discussion, relative to the extant art: U.S. Pat. Nos. 3,965,686 ('686), issued Jun. 29, 1976, entitled DRAIN SHEET MATERIAL; 4,995,759 ('759), issued Feb. 26, 1991, entitled DRAINAGE TUBE CONSTRUCTION; 6,527,474 ('474), issued Mar. 4, 2003, entitled PAVEMENT DRAIN; 4,019,326 ('326), issued Apr. 26, 1977, entitled NONWOVEN HORIZONTAL DRAINAGE SYSTEM; and, 5,152,892 ('892), issued Oct. 6, 1992, entitled SPIRAL FILTER ELEMENT. All of these patents show, to some degree, the functionality of the coiled or spiral element in providing a conduit for fluids and having a relatively low or limited deformation character. However, it is in the careful study of each disclosure that one perceives, albeit suitability for intended purpose, its limitations in broad spectrum applicability, as noted above.
Issued to Saito et al., '686 details a compound sheet apparatus wherein a plurality of coils or internally-strengthened tubules are parallel-arrayed, embedded in a non-woven fibrous material and disposed between two thin sheets of filter fabric. The apparatus' outer sheets are both porous and not suitable for placement against vertical walls. Most limiting is the necessity for the fibrous “filling” in which the tubules are embedded. When used for the specific purpose shown in '686, and notwithstanding the “filling”, the apparatus appears to enjoy some flexibility; however, it seems intuitive that doubling the thickness of the “sandwich” would render such flexibility problematical. A characteristic of its construction, the use and dependence upon flow direction-constraining fibers, obviates a bi-directional emplacement of the apparatus on surfaces that may change in pitch direction or present a configuration that will not allow the use of a constrained-flow device.
A single-purpose drainage tube, for use in entrenchments, is shown in '759. The apparatus consists of a length of drain formed by a fixed tangential connection of parallel, equal-length sections of tubing, on a longitudinal axis that is perpendicular to the axes of the sections. The tubing consists of corrugated pipe; and, the assembly is completed by enveloping the above apparatus in a filter fabric. Although more stylized emplacements can be conceived for the apparatus, it appears that in the vertical drainage mode, turning of corners is impossible because the longitudinal fixation denies flexibility, as defined and required by the instant inventor.
Although not intended to flex, the pavement drain member of '474 is remarkable in that it is essentially a plain resin coil, albeit composed of two arcuate strands in fixed adjacency. The coil possesses a minimal gap between each annular section so as to obviate infusion of macadam, when it is set onto the asphalt medium. Water will infuse readily into the coils and be transported from the tarmac base. The primary motivation for the use of a stylized resin coil is to provide a structure having high overburden sustainability, a tunnel-like effect for transporting fluids and a possession of pseudo-homogeneity with the tarmac. The latter characteristic obviates coil interference during destruction (by grinding) of the tarmac.
The subsurface soil drainage system of '326 employs a porous mat, of non-woven fibers, in which is centrally embedded a tunnel-shaped agglomeration of heat-spun filaments of spiral or coil geometries. Subsurface waters, infusing the mat, are carried off through the tunnel of filaments, thus draining the surrounding soil. This apparatus requires a considerable thickness (and amount) of non-woven mat, making it unsuitable for the purposes of draining most structures. It also appears to lack the degree of flexibility required by the instant inventor.
Final to this review of relevant art is patent '892, for a spiral filter element possessing a special expansion-compression character. It is essentially a filter-covered spring, the coils of which are formed so that the gaps between the (analogical) annuli gradually increase in size from one coil end to the other. This predisposition of the element assures that, when vertically and operatively oriented, each discrete section of the coil is capable of sustaining the mass of the coil sections above it. Placed in a horizontal position, the spring gap variations of this element would defeat its purpose in any planar filtration ensemble.
Although for the most part, structure and soil draining, with concomitant filtration, is still performed using tiles, large amounts of stone and paper/fabric overlay (such as in drywell and septic usages), it is the instant inventor's contention that conscientious builders should transition to more effective and reliable draining and filtering modalities.
The instant invention provides an easily manipulated, flexible device that can be emplaced both adjacent to and beneath concrete structures and earthen constructs, as well wrapped about articles such as pipes, cylinders, corners and generally planar surfaces. Its use clearly obviates the need for stone, gravel and other filtering mechanisms.